1971 Riviera tire size options.

Discussion in 'A boatload of fun' started by crazyjackcsa, May 12, 2013.

  1. crazyjackcsa

    crazyjackcsa Big and Untame

    Getting new tires again for the Riviera. Looking for opinions/fit issues.

    I'd like to get a little rake going on the car but I'm not sure if adjusting tire size is "cheating"

    Anyway, 225/75/R15's all around at this point. I was thinking of going 215/75 up front and 235/75 in the back. I have stock rally wheels.

    I guess my questions are as follows.

    How much of a difference can you go with on a street car before it looks silly? What will fit our rims/wheelwells? How small in the front? How big in the rear?

    Blackwall, whitewall or raised white letter?
     
  2. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    If you can find 80's wagon 15x7 wheels, your options open up over the stock 15x6. Look at www.tirerack.com for 6" width tires, the width options are limited. Just a suggestion...
     
  3. crazyjackcsa

    crazyjackcsa Big and Untame

    That's not going to be happening. Like I said 225/75 fits fine and is actually slightly smaller than the H78-15 that came with them originally.

    TT
     
  4. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    It was just a suggestion and what I did on my '72 Riv. No problem with room in the wheel wells. You can go to tire rack as I suggested, but putting on 235's is pushing it. Sounds like you know what you want based on your answer to my post.
     
  5. robs71redriv

    robs71redriv robs71redriv

    the 225 front and 235 rear work great (I have a late 70's combo of that (both say replaces H78-15 on side wall)
    You dont notice looking it - 225 is slightly smaller than H-78 - 235/75 s bit larger but not enough to matter. 235/70 would be pretty much same diameer as 225/70 so that is a good combo too - closest to 71 H-70 tire option

    all the original tire options and sizes and production numbers are in
    <center> [​IMG]</center>
    Boattail Riviera Option-Production Numbers - Prices - Availability-Colors
     
  6. crazyjackcsa

    crazyjackcsa Big and Untame

    Hey Ken, I didn't mean any disrespect, but around here in my parts, finding a cheapo set of wheels would be like finding the holy grail. And purchasing new is out of the question, so I'm limited to what I have.
     
  7. JZRIV

    JZRIV Platinum Level Contributor

    No problem with the 215s through 235s on the 15x6 wheels. As Ken mentioned the later 15x7 wheel would open up more options to go bigger/wider.
    you might consider adjusting coil springs if you want rake or better yet adjustable like this. http://www.ebay.com/itm/1971-1976-P...Riviera|Year:1971&hash=item1c324c66fc&vxp=mtr

    215s are on the small side for a big heavy boat. As far as looking silly thats in the eye of the beholder. I've seen 71 Rivs raised in the back with wider tires and they look totally cool retro 70ish.
     
  8. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    No worries, Trevor. :beers2:
     
  9. PTinVT

    PTinVT Well-Known Member

    71 Riv - looking to plus-size

    Cool, a current "71 riv option tire options" thread :) I realize this was about staying on 15" wheels, but rather than start a new thread, this seems relevant. (and germane to the subject line, for anyone searching later)

    I'm currently running modern stock equivalents 225/75/15 on stock 15x6 rally wheels. I'd like to go for a bigger wheel mainly for looks, but also a little more handling confidence - I don't mind trading a rougher ride for more control.

    There are probably more 16" options but if I'm going to the trouble and expense, I'd like to go 17". Not looking to stagger or go too nuts with the wheel/tire width but hoping to get a slightly wider stance to fill up those cavernous wheel wells. Of the wheel/tire options, trading off price/looks, I'm finding decent 17x8 wheel options and 235/55/17 tire options and am thinking about this combo.

    Does anyone know the stock rally wheel offset? I'm told the big-car option of this time was wheel "WK" I've found posts suggesting they have a 4" "backspace" which equates to a +12 offset if I can believe the conversion charts I've found.

    I've tried searching but I can't find much non-stock wheel/tire chatter for boattails :) I'm also about to replace my old springs (ordered from ESPO) with the hope of staying at stock height.

    Any and all input appreciated.
    Thanks v8buick.com
     
  10. theone61636

    theone61636 Well-Known Member

    Re: 71 Riv - looking to plus-size

    The backspacing isnt quite 4"; more like 3 7/8. If you're going with a 17" wheel why only use a 235 series tire? You could easily fit a 275 series tire in the rear with the proper backspacing.
     
  11. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    With a 17" wheel as described, what size front tire would fit without rubbing and have a similar diameter?

    Thanks!
     
  12. theone61636

    theone61636 Well-Known Member

    A 245/55 more than likely on a 17x8 rim, I wouldn't even be afraif to go as short as a 245/45 (25.7" diameter). Granted this will screw up your speedo and you won' have as much sidewall but if you're looking for better handling and street performance a shorter tire would help as long as you get a tire with the proper load capacities.
     
  13. PTinVT

    PTinVT Well-Known Member

    Re: 71 Riv - looking to plus-size

    I actually like the Vogue tires (inner whitewall with outer gold stripe) - for me, white letter tires are too muscly for this car, blackwalls look out of place, and regular whitewalls don't seem to go with the kind of wheels I'm looking at (for example, American Racing classic 5-spoke "Torq Thrust"). The Vogues dont' come in a lot of readily available sizes, but 235-55/17 is one of them (a common modern Cadillac size, I believe). I'm not looking to go staggered and I drive this car maybe 1000 miles a year, tops.

    Other than the fact that yes, I could go wider, do you see any downside or problems to the combo I'm considering?

    Thank you for all the input.
    -Peter
     
  14. Gary Farmer

    Gary Farmer "The Paradigm Shifter"

    Heck if it were me, I'd use the 225/70r15's, which are supposed to be the ideal size for that car anyway. You could go a size up or down in either direction and be fine, but the best balance for tire wear is 225/70's. Best all-around traction, wear, handling characteristics, and road friction for gas mileage.

    Always remember the big number is the width in milimeters, multiplied by the smaller number as a percentage. This means on a 225/70r15 has a 225 mm width and the height of the tire (from rim to road) is 225x70% or 225 times .7 = 157.5 mm.

    I always heard the 70 series were the best balance for tire wear. Used to be (not sure if it is now) 235 was the largest you could go on 15" rims.
     
  15. crazyjackcsa

    crazyjackcsa Big and Untame

    I went with 235/75 on the rear and 225/75 up front. It's a very tall wheel on the back. I think next time I might go with 235/75 in the back and a 215/75 in the front.

    Everybody is different of course, and it's just my opinion but these big cars look good with big tires.

    [​IMG]
     
  16. PTinVT

    PTinVT Well-Known Member

    And I went with my original proposition, 17x8 (-11ET) American Racing "Torq Thrust 2" with Vogue 235-55/17 whitewall/gold stripe tires.

    Just got her back from the shop today. I am rather pleased with how it all came out :bglasses:
     

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  17. Tomahawk

    Tomahawk Gold Level Contributor

    Thanks for the pic...I'm in the market for new tires and rims, and wasn't sure what a 275/55/17 (28.9" overall diameter) would look like. I'm going with these 17x8 rims by MB:


    mbmos.c.ang.jpg
     
  18. crazyjackcsa

    crazyjackcsa Big and Untame

    Clearly, you'll have more wheel and less tire, but it'll give you an idea. They are stock rims, so 235 is as wide as I can reasonably go. Would love to go with some thing wider. It's been a year and I'm really happy with them.
     
  19. Tomahawk

    Tomahawk Gold Level Contributor

    Right, you'll have about an inch more of rubber all around, but I agree that these cars look great when you fill up the wheel wells with wheels.

    If you ever decide to buy wider rims, this may help:
     

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  20. Tomahawk

    Tomahawk Gold Level Contributor

    Well that didn't turn out well at all...it's just a spreadsheet converting aspect ratios to overall OD with the different size wheels. If you want, I can email it to you
     

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